Approved lists allow messages from approved senders to bypass IP-level filtering. The Approved lists are not applied to your MTA, but you can set up additional approved or blocked senders, or perform additional filtering at your MTA. The trade-off for bypassing IP filtering is the additional resources that are needed to process, filter, and store the higher levels of spam messages that would otherwise have been blocked.
In the case of a standard reputation (Known Spam Source List) service lookup, the order of the evaluation hierarchy is:
For dynamic reputation (QIL) service lookup, the customer-defined “blocked policy lists” (IP, Country) are ignored and only the Approved lists are checked. Otherwise, the order of policy lookup (first IP, then country) is the same as for standard reputation (Known Spam Source List) service.
Avoid specifying overlapping CIDR ranges in the Approved and Block lists because the Block list might take priority over the Approved list.
To add to the Approved list:
Be very selective when adding a country as you might also be adding known spammers to the approved list.
When specifying the IP address, you can use either of the following:
Standard IPv4 format: 22.214.171.124
IPv4 IP address range in CIDR notation: 126.96.36.199/24
Avoid specifying the same CIDR range in the Approved and Blocked lists, as unexpected results might occur. If required, the approved CIDR range must be less than or equal to the blocked CIDR range.
For example, avoid specifying 172.31.15.164/30 in the Approved list and 172.31.15.164/31 in the Blocked list
Standard IPv6 format: